• KIEAE Journal
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• 제16권4호
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• pp.79-86
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• 2016

Purpose: Frequently, the apartment management offices have difficulties in effective repair works due to their insufficient technological capability to operate long-term repair program. There also have been many cases of failure in executing urgent repairs mainly because the repair allowance has not accumulated enough for the repair works on time. This study aimed to determine core items in apartment maintenance in order to reduce the confusion and unnecessary efforts for the management office by suggesting simple list of repair items. Method: Core items are defined using several indicators. The degrees of necessity for repair work(NRW) are calculated combining the impacts to living, safety, and aesthetics. Then the degrees of burden of repair cost(BRC) are estimated by analyzing actual long-term repair program of three apartment complexes. Lastly the degrees of accumulation demand for repair allowance(AD) are calculated with NRW and BRC. Result: The core items and essential items are suggested for three apartment types as case studies based on the indicators of NRW, BRC, and AD. Then, the required accumulated allowance per $m^2$ was calculated to effectively implement repair works.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3665-3676
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• 2023

The use of ion exchange resins to remove ionic impurities from solution is prevalent in industrial process systems, including in the primary heat transport system (PHTS) purification circuit of nuclear power plants. Despite its extensive use in the nuclear industry, our general understanding of ion exchange cannot fully explain the complex chemistry in ion exchange beds, particularly when operated at or near their saturation limit. This work investigates the behaviour of mixed-bed ion exchange resin, saturated with species representative of corrosion products in a CANDU (Canadian Deuterium Uranium) reactor PHTS, particularly with respect to iron chemistry in the resin bed and the removal of lithium ions from solution. Experiments were performed under deaerated conditions, analogous to normal PHTS operation. The results show interesting iron chemistry, suggesting the hydrolysis of cation resin bound ferrous species and the subsequent formation of either a solid hydrolysis product or the soluble, anionic Fe(OH)₃^-.

• 열처리공학회지
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• 제14권6호
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• pp.336-344
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• 2001

For the establishment of the world wide unified scales of the Rockwell hardness test with conical indenters, round robin test was carried from 1998 to 2000. The pilot laboratory was MPA-NRW and 12 laboratories from 11 countries participated In this RRT. Rockwell hardness of 74 specially prepared blocks was measured for the scales of C, A, D, 45N, 30N, and 15N and the results were compared. It was found that the geometric form of indenter affects on the results very significantly and standardization in the measurement and evaluation of indenter should be established in short time for the reliable hardness measurement. KRISS showed good results in general for all of the ranges except 15N scale which showed relatively large difference compare to the mean value. It was concluded that poor control in loading velocity of the dash pot was the major reason.

• 한국조경학회지
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• 제22권2호
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• pp.105-122
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• 1994

The landscape plannings were composed of the fundamental provisions which are important factors for the city and local plannings in Germany. The State Government run institute like LOLF in NRW have been established to solve the serious ecological problems. The institute have completed the basic system covering various ecological problems, such as environmental affection analysis and ecological risk, to contribute the application of the various land-using plants. The ecological landscape plannings are regarded as major fundamental plans of environmental preservation for the plannings development. The problems about the local landscape plannings needed to be preserved ecologically are introduced into the Federal Nature Preservation Law and State Congress Law in order to carry out the environmental protection policy effectively. The local landscape plannings are divided into two-step models by the special classification system for the planning. One is build-up of an independent design separated from city plans functionally, and the other is a systematic regulation for cooperation between the local plans and ecological conservation functions. The local plannings including lands to be preserved as the Nature Preservatin Zone is classified a rest area total sectioned plains.

• 상하수도학회지
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• 제33권4호
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• pp.299-309
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• 2019

Waterworks facilities inevitably experience some amount of leakage even if there is a lot of investment or state-of-the-art technology that is applied such as DMA(District Metered Area) system construction, leakage detection, repair, pipe rehabilitation, etc. The primary reason is the leakage is naturally restored over time. In the UK, this restoration characteristic is defined as NRR(Natural rate of rise of leakage) and used to decision making for prioritizing active leakage control of DMAs. However, this restoration characteristic is well recognized, but researches on NRR in the water distribution system are insufficient in Korea. In this study, the estimation method of NRR was developed suitable for applicating in Korea considering of SCADA data, water infrastructure, and water usage patterns by modification of the UK's NRR method. The proposed method was applied to 9 DMAs and verified it's applicability by comparing with the other water loss performance indicators. It is expected that the proposed method can be used to support decision making for sustainable NRW(Nor-revenue water) management in the water distribution system.

• Journal of Microbiology and Biotechnology
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• 제26권10호
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• pp.1736-1745
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• 2016

The interactions of microbiota in the gut play an important role in promoting or maintaining the health of hosts. In this study, in order to investigate and compare the effects of dietary supplementation with Lactobacillus pentosus HC-2 (HC-2), Enterococcus faecium NRW-2, or the bacteria-free supernatant of a HC-2 culture on the bacterial composition of Litopenaeus vannamei, Illumina sequencing of the V1-V2 region of the 16S rRNA gene was used. The results showed that unique species exclusively existed in specific dietary groups, and the abundance of Actinobacteria was significantly increased in the intestinal bacterial community of shrimp fed with the bacteria-free supernatant of an HC-2 culture compared with the control. In addition, the histology of intestines of the shrimp from the four dietary groups was also described, but no obvious improvements in the intestinal histology were observed. The findings in this work will help to promote the understanding of the roles of intestinal bacteria in shrimps when fed with probiotics or probiotic supernatant.

• 한국인터넷방송통신학회논문지
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• 제14권1호
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• pp.161-167
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• 2014

본 논문에서는 밀리미터파 대역에서 다양한 매질들에 대한 유전적 특성의 측정을 통해 유전율 결과를 제시하였다. 밀리미터파는 짧은 파장과 넓은 대역폭을 가지고 있어 부품의 소형화, 경량화가 가능하고, 정보의 대량 전송이 가능하다는 장점을 가지고 있기 때문에 그 연구의 필요성이 높아지고 있다. 이 대역의 전파는 직진성이 뛰어나고 회절성이 작으며 여러 물질들에서 전파가 흡수되어 불필요한 간섭이 잘 발생하지 않는 특징을 가지고 있다. 그렇기 때문에 밀리미터파 대역의 전파가 진행하는 과정에서 반사 투과하는 다양한 매질들의 전기적인 특성에 대한 분석이 중요할 것이다. 따라서 본 논문에서는 밀리미터파 대역에서 Free Space 방식을 이용하여 물질의 반사 투과 특성을 측정하였다. 이를 활용하여 Nicolson-Ross Weir 유전율 계산법을 이용해 다양한 매질들의 유전율을 도출하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.260-266
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• 2009

본 연구는 지방상수도 배급수 관망의 유수율을 향상시키기 위하여 수량관리를 위한 블록시스템 구축을 통한 구역화 계량, 누수의 정량화를 위한 야간최소유량 측정을 통한 누수평가지표 및 국제 누수지수ILI(Infrastructure Leakage Index)의 도입, 압력제어를 통한 누수저감 효과분석, 장기적인 계획수립을 위하여 노후수도관의 잔존수명 예측 등 누수를 평가 관리할 수 있는 기술을 개발, 제안하였다. N시 야간최소유량 측정을 통하여 주거지역과 상업지역에서 정량적인 누수평가지표로 관길이당, 급수전당의 허용기준누수량을 산정하였다. 이는 관망정비가 완료된 주거, 상업지역을 각각 대상으로 UK water industry에서 제안한 방법을 이용하여 실측을 통한 야간최소유량을 분석함으로써 유수율을 대신할 수 있는 허용누수량 산정식을 개발하였다. 압력제어를 통한 누수저감효과는 감압변의 설치를 통하여 수행되는데, 사천시 우티 배수구역을 대상으로 압력관리 구역을 4개로 분할하고 감압밸브 3개소, 가압펌프 1개소를 설치하여 압력을 조절한 결과 약 $466\;m^3/day$의 누수를 저감시킬 수 있을 것으로 나타나 압력관리를 통하여 연간 113백만의 비용절감효과가 기대되었다. 노후 상수관로의 부식속도 및 잔존수명 예측 연구에서는 매설년도, 토양 또는 수질특성에 따른 관체의 부식속도를 평가함으로써 잔존두께를 예측할 수 있는 모델을 개발하였으며 또한 부식으로 인한 공식특성에 따른 잔존강도 등을 평가할 수 있는 비선형회귀 모형을 개발, 수도관의 잔존수명예측에 활용하여 장단기 노후관 개대체 계획수립에 활용할 수 있도록 제안하였다. 본 연구의 결과들은 지방상수도의 유수율 제고 및 관망정비사업에 적극적으로 활용할 수 있는 누수평가 및 관리기법을 제안할 수 있을 것으로 기대된다.